For example, angle-measuring devices are used as rotary encoders for determining the angular position of two machine components that are rotatable relative to each other. Additionally, length-measuring devices measure a linear displacement of two machine components that are displaceable relative to each other. Angle-measuring devices as well as length-measuring devices are usually equipped with sensor units which scan components that are movable relative to the sensor units, e.g., angle scales, linear scales, or measuring standards, and generate position-dependent signals.
In the case of optical measuring devices, light sources and photodetectors are often mounted on a circuit board of an optical sensor unit. An optical scale is situated opposite from the circuit board and is set apart by an air gap. Signals are able to be generated as a function of the position, in accordance with, e.g., conventional principles.
Such measuring systems or measuring devices are often used for electrical drives, for the purpose of determining the relative movement or the relative position of corresponding machine components. In such a case, using a corresponding interface system, the generated position values are made available to a subsequent electronics unit for the control of the drives.
German Published Patent Application No. 198 43 155 describes a displacement-measuring device in which the corresponding sensor unit includes an IC chip, which is mounted on a glass substrate in a resin block.